#+NAME: defmember
#+begin_src scheme :noweb yes :results none :exports code :eval never-export :language guile
(define member?
  (λ (a lat)
    (cond
     [(null? lat) #f]
     [else
      (or (eq? a (car lat))
          (member? a (cdr lat)))])))
#+end_src

Lets test it:

#+NAME: usemember
#+begin_src scheme :noweb yes :results output :exports both :eval never-export
<<defmember>>

(display
 (simple-format
  #f "(member? 1 '(3 2 1)) -> ~a\n"
  (member? 1 '(3 2 1))))

(display
 (simple-format
  #f "(member? 1 '(3 2 4)) -> ~a\n"
  (member? 1 '(3 2 4))))
#+end_src
